Apparatus and method to efficiently send device trigger messages

ABSTRACT

With the proliferation of Machine-Type Communication (MTC), an excessive use of device trigger messages in a Long Term Evolution (LTE) network can have negative effects on user equipment (UE). These effect can include a shortening of UE battery life and/or excessive signalling caused by the frequent changing from an idle mode to an active mode. An MTC Interworking Function (MTC-IWF) can be configured to determine the status of a UE to which a device trigger message is intended. If the device trigger message is low priority and the UE is in an idle state, the MTC-IWF or Mobile Management Entity (MME)/Serving GPRS Support Node (SGSN)/Mobile Switching Center (MSC) can buffer the device trigger message.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Patent Application Ser. No. 61/667325, filed Jul. 2, 2012,incorporated herein by reference in its entirety.

TECHNICAL FIELD

Embodiments pertain to wireless communications. Some embodiments pertainto wireless communications used in Long-Term Evolution (LTE) networks.

BACKGROUND ART

Device triggering is the means by which a service capability server(SCS) sends information to a piece of user equipment (UE) via a networkto trigger the UE to perform application specific actions.

A large number of device triggering messages, coupled with small datarequests, may cause signaling surge in the network and have an impact onthe battery life of a UE if the UE toggles between an idle state and aconnected state. This is especially true for mobile data applicationsthat send device trigger messages with a small amount data frequently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrated overview of an embodiment of the presentinvention.

FIG. 2 is a flowchart illustrating the operation of an embodiment of thepresent invention.

FIG. 3 is a flowchart illustrating the operation of another embodimentof the present invention.

FIG. 4 is a flowchart illustrating the operation of another embodimentof the present invention.

FIG. 5 is a flowchart illustrating the operation of another embodimentof the present invention.

FIG. 6 is a flowchart illustrating the operation of another embodimentof the present invention.

FIG. 7 is a flowchart illustrating the operation of another embodimentof the present invention.

DESCRIPTION OF THE EMBODIMENTS

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Examples merely typify possible variations.Individual components and functions are optional unless explicitlyrequired, and the sequence of operations may vary. Portions and featuresof some embodiments may be included in, or substituted for, those ofother embodiments. Embodiments set forth in the claims encompass allavailable equivalents of those claims.

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known method, procedures, components, and circuitshave not been described in detail so as not to obscure the presentinvention.

Although embodiments of the invention are not limited in this regard,the terms “plurality” and “a plurality” as used herein may include, forexample, “multiple” or “two or more.” The terms “plurality” or “aplurality” may be used throughout the specification to describe two ormore components, devices, elements, units, parameters, and the like. Forexample, “a plurality of stations” may include two or more stations.

The 3rd Generation Partnership Project (3GPP) is a collaborationagreement established in December 1998 to bring together a number oftelecommunications standards bodies, known as “Organizational Partners,”that currently include the Association of Radio Industries and Business(ARIB), the China Communications Standards Association (CCSA), theEuropean Telecommunications Standards Institute (ETSI), the Alliance forTelecommunications Industry Solutions (ATIS), the TelecommunicationsTechnology Association (TTA), and the Telecommunication TechnologyCommittee (TTC). The establishment of 3GPP was formalized in December1998 by the signing of the “The 3rd Generation Partnership ProjectAgreement.”

3GPP provides globally applicable standards as Technical Specificationsand Technical Reports for a 3rd Generation Mobile System based onevolved GSM core networks and radio access technologies that theysupport (e.g., Universal Terrestrial Radio Access (UTRA) for bothFrequency Division Duplex (FDD) and Time Division Duplex (TDD) modes).3GPP also provides standards for maintenance and development of theGlobal System for Mobile communication (GSM) as Technical Specificationsand Technical Reports including evolved radio access technologies (e.g.,General Packet Radio Service (GPRS) and Enhanced Data rates for GSMEvolution (EDGE)). Technical Specifications for current standardsrelated to mobile telephony are generally available to the public fromthe 3GPP organization.

3GPP is currently studying the evolution of the 3G Mobile System andconsiders contributions (views and proposals) directed toward theevolution of the UTRA Network (UTRAN). A set of high-level requirementswas identified by 3GPP workshops including: reduced cost per bit;increased service provisioning (i.e., more services at lower cost withbetter quality); flexibility of use of existing and new frequency bands;simplified architecture with open interfaces; and reduced/reasonableterminal power consumption. A study on the UTRA & UTRAN Long TermEvolution (UTRAN-LTE, also known as 3GPP-LTE and E-UTRA) was started inDecember 2004 with the Objective to develop a framework for theevolution of the 3GPP radio-access technology towards a high-data-rate,low-latency and packet-optimized radio-access technology. The studyconsidered modifications to the radio-interface physical layer (downlinkand uplink) such as means to support flexible transmission bandwidth upto 20 MHz, introduction of new transmission schemes, and advancedmulti-antenna technologies.

3GPP-LTE is based on a radio-interface incorporating orthogonalfrequency division multiplex (OFDM) techniques. OFDM is a digitalmulti-carrier modulation format that uses a large number ofclosely-spaced orthogonal sub-carriers to carry respective user datachannels. Each sub-carrier is modulated with a conventional modulationscheme, such as quadrature amplitude modulation (QAM), at a (relatively)low symbol rate when compared to the radio frequency (RF) transmissionrate. In practice, OFDM signals are generated using the fast Fouriertransform (FFT) algorithm.

Machines often need to communicate with other machines without little orno human intervention. In the past, such communications were made viawire. As time went on, wireless communications began to be used. Withthe increased availability of mobile broadband, machine typecommunications (MTC) via broadband is becoming more and more popular.MTC enables communications between remote machines for exchanginginformation and operating commands without the need for humanintervention. Exemplary uses of machine-type communications includeremote sensors, e-health, remote-controlled utility meters, surveillancecameras, toll payments, production chain automation, and the like. Forexample, a device can monitor the operation status of another device andreport the statuses to a central server. Or a device can read a utilitymeter and provide the data to a billing department for the preparationof monthly utility bills.

When a server wishes to activate or trigger a certain MTC device, it maytransmit a device trigger message over the service network. The devicetrigger message may be configured to initiate communication between theMTC device and the server.

Sending device trigger messages is the means by which a ServicesCapability Server (SCS) sends information to the User Equipment (UE) viathe 3GPP network to trigger the UE to perform application specificactions. These actions may include initiating communication with the SCSfor the indirect model or an Application Server (AS) in the network forthe hybrid model. Device Triggering may be required when an IP addressfor the UE is not available or reachable by the SCS/AS.

A device trigger message typically contains information (e.g.,IMSI<Application port ID, and the like) that allows the network to routethe message to the appropriate UE and for the UE to route the message tothe appropriate application. The information destined to the applicationis referred to as the device trigger payload. The UE is arranged to beable to distinguish between a message that contains device triggeringinformation from any other type of message.

Upon reception by the UE, the device trigger payload is examined todetermine the information that triggers application related actions. Theapplication in the UE may perform certain indicated actions, such as toinitiate an immediate connection or to make a later communication to theSCS or AS, based on the information in the trigger payload.

A Charging Data Record (CDR) may be collected for the device triggering.That is, the provider may keep track of the cost of the datatransmission for future billing purposes.

With reference to FIG. 1, a block diagram illustrating the architecturefor Machine Type Communication (MTC) under 3GPP is shown.

A UE 102 is shown as executing an MTC UE application 104. The UE iscoupled to a Radio Access Network (RAN) 106. Via RAN 106, the UE iscoupled to various components of the Evolved Packet Core, such as MobileSwitching Center (MSC) 108, Mobile Management Entity (MME) 110, ServingGPRS Support node (SGSN) 111 and Serving Gateway (S-GW) 112. Together,these components comprise the Visited Public Land Mobile Network(VPLMN). Components in the Home Public Land Mobile Network (HPLMN) arecoupled to the above components via several reference points.

MME 110, along with SGSN 111 may be arranged to perform the followingfunctionality: receive a device trigger message from MTC-IWF;encapsulate device trigger information in a NAS message sent to the UEused for MTC; receive device trigger acknowledgement from the triggeringUE; report device trigger delivery success/failure status to MTC-IWF;and provide SGSN/MME congestion/load information to MTC-IWF.

Reference point Tsp (120) is used by a services capability server tocommunicate with an MTC InterWorking Function (MTC-IWF) 130. Referencepoint T5a (122) is used to couple MTC-IWF and SGSN 111. Reference pointT5b (124) is used to couple MTC-IWF and a serving MME. Reference pointT5c (126) is used to couple MTC-IWF and a serving MSC. Reference pointS6 (28) is used to couple MTC-IWF and the Home Subscriber Server.

An MTC-IWF 130 may be a standalone entity or a functional entity locatedwithin another network entity. An MTC-IWF may reside in a Home PublicLand Mobile Network (HPLMN). MTC-IWF may have many different functions,including, but not limited to: termination of the Tsp, S6m and Rf/Gareference points; termination of one or more reference points among T4,T5a, T5b and T5c; ability to authorize the SCS before communicationestablishment with the 3GPP network; ability to authorize control planerequests from an SCS.

MTC-IWF 130 may also support the following device triggerfunctionalities: reception of a device trigger request from SCS; reportto the SCS the acceptance or non-acceptance of the device triggerrequest; report to the SCS the success or failure of a device triggerdelivery; may apply MTC-IWF and/or SGSN/MME induced congestion/loadcontrol as part of the response to trigger requests; and uses astandardised identifier (e.g. Application Port ID) to allow the UE todistinguish an MT message carrying device triggering information fromany other type of messages.

MTC-IWF 130 may also support: a Home Subscriber Server (HSS) resolutionmechanism for use when multiple and separately addressable HSSs havebeen deployed by the network operator; interrogation of the appropriateHSS, when needed for device triggering, to: a) map E.164 MSISDN orExternal Identifier to IMSI; b) retrieve serving node information forthe UE (e.g. serving SGSN/MME/MSC identifier); and c) determine if a SCSis allowed to send a device trigger to a particular UE.

MTC-IWF 130 may also support selection of the most efficient andeffective device trigger delivery mechanism and shielding of this detailfrom SCS based on: current UE serving node information from HSS/HLR(e.g. serving MME/SGSN/MSC identifier); the device trigger deliverymechanisms supported by the UE; the possible device trigger deliveryservices supported by the HPLMN and, when roaming, VPLMN; operatordefined device trigger delivery policies, if any; and/or optionally, anyinformation received from the SCS; protocol translation, if necessary,and forwarding towards the relevant network entity (i.e. servingSGSN/MME/MSC or SMS-SC inside HPLMN domain) of a device trigger requestto match the selected trigger delivery mechanism; generation of devicetrigger CDRs with External Identifier and SCS Identifier and forwardingto CDF/CGF over instance of Rf/Ga; and ability for secure communicationsbetween the 3GPP network and the SCS.

Although only a single MTC-IWFs is illustrated in FIG. 1, it should beunderstood that multiple MTC-IWFs may operate within a single HPLMN.

Home Subscriber Server (HSS) 150 may be configured to support thefollowing functionalities: termination of the S6m reference point whereMTC-IWFs connect to the Home Location Register (HLR)/HSS; stores andprovides to MTC-IWF (and optionally to MTC AAA) the mapping/lookup ofthe Mobile Station International Subscriber Data Number (MSISDN) orexternal identifier(s) to International Mobile Subscriber Identify(IMSI) and subscription information used by MTC-IWF for devicetriggering; mapping of MSISDN or external identifiers to IMSI;optionally, mapping from External Identifiers to MSISDN is also providedfor legacy SMS infrastructure not supporting MSISDN-less SMS; HSS stored“Routing information” including serving node information if availablefor the UE (e.g. serving SGSN/MME/MSC identifier); and determine if aSCS is allowed to send a device trigger to a particular UE; terminationof the S6n reference point; provides to MTC-AAA the mapping between IMSIand External identifier(s).

Services Capability Server 132 is arranged to couple an applicationserver 134 to MTC-IWF 130 in an indirect model. In a direct model,application server 136 is coupled directly to the operator network inorder to perform direct user plane communications with the UE withoutthe use of an external SCS.

As explained above, a large amount of device triggering, coupled withsmall data requests, can cause a signaling surge in the network. Thiscan lead to a negative impact on the battery life of a piece of userequipment (UE) because the UE may have to toggle between an idle and aconnected state more often than required. There are several possiblesolutions.

With reference to FIG. 2, a flowchart presenting an embodiment is shown.In this embodiment, the MTC InterWorking Function (MTC-IWF) obtains thestate of the UE from a home subscriber service (HSS), using an indirectmodel.

A Services Capability Server (SCS) determines the need to trigger thedevice (202), if the SCS has no contact details for an MTC-IWF, it mayfirst determine the IP address(es)/port(s) of an MTC-IWF by performing aDNS query using the External Identifier or using a locally configuredMTC-IWF identifier (204).

Thereafter, the SCS sends a Device Trigger Request message to theMTC-IWF (206), The message may contain information such as an Externalidentifier or MSISDN, SCS Identifier, trigger reference number, validityperiod, priority, Application Port ID, trigger payload, and the like.The SCS includes a Trigger Payload that may contain the informationdestined for the MTC application, along with the information to route itto the MTC application. The Application Port ID is set to address atriggering function within the UE.

It should be noted that terms such “Device Trigger Request” message ismerely used for illustration. The actual name of the message used maydiffer.

The MTC-IWF checks that the SCS is authorized to send trigger requestsand that the SCS has not exceeded its quota or rate of triggersubmission over Tsp (208). If this check fails the MTC-IWF sends aDevice Trigger Confirm message with a cause value indicating the reasonfor the failure condition and the flow stops at this step.

The MTC-IWF sends a Subscriber Information Request (SIR) message to theHSS to determine if SCS is authorized to trigger the UE. (ExternalIdentifier or MSISDN and SCS Identifier, UE State Information Request)to resolve the External Identifier or MSISDN to IMSI, retrieve theidentities of the UE's serving CN node(s) (210). The LE StateInformation Request flag is set to request the UE state information(such as Idle, Connected, and registered) from HSS (212). Thisinformation also tells HSS to register for Reachability Notification incase UE is not reachable.

The MTC-IWF may be configured to perform cache authorization and routinginformation for the UE. However, this may increase the probability oftrigger delivery attempt failures when the cached serving nodeinformation is stale.

The HSS sends the Subscriber Information Answer (IMSI and servingnode(s) identities, UE State Information) message (214). HSS policy mayinfluence which serving node identities are returned. If the cause valueindicates the SCS is not allowed to send a trigger message to this UE orvalid subscription information was not returned by the HSS, the MTC-IWFsends a Device Trigger Confirm message with a cause value indicating thereason for the failure condition and the flow stops. Otherwise, thisflow continues.

If the UE is not reachable, HSS may not send serving nodes identities orstate information which provides implicit indication that UE is notreachable and MTC-IWF in this case will store the trigger if validityperiod does not indicate single attempt delivery.

Thereafter, the MTC-IWF obtains the state of HE in the SubscriberInformation Answer message and decides whether to buffer the triggermessage or to deliver it (216). This process may take place in one ofseveral different manners. One example is detailed further with respectto FIG. 3. When the MTC-IWF decides to send the device trigger message,it selects a trigger delivery procedure based on the informationreceived from HSS and local policy. The delivery procedure is selectedand the MTC-IWF attempts a trigger delivery procedure (218).

The MTC-IWF sends the Device Trigger Report (External Identifier orMSISDN and trigger reference number) message to the SCS with a causevalue indicating whether the trigger delivery succeeded or failed andthe reason for the failure (220). The MTC-IWF generates the necessaryCDR information including the External Identifier or MSISDN and SCSIdentifier (222).

In response to the received device trigger, the UE takes specificactions that take into consideration the content of the trigger payload(224). This response typically involves initiation of immediate or latercommunication with the SCS or an AS. This action depends on the natureof the UE being tasked.

With reference to FIG. 3, a flowchart presenting the MTC-IWF behaviorupon receiving the UE state information. After receiving the SubscriberInformation Answer message (302), the MTC-IWF validates the subscriberand checks the state of the UE (304). The priority of the device triggeris then checked (306). If the device trigger is high (308), then thedevice trigger is delivered (310). If the priority is low (312), thenthe UE state is checked (314). If the UE is connected (316), then thedevice trigger is delivered (310). If the UE is idle (318), then thedevice trigger is buffered (320). Then a counter is incremented (322).If the counter has reached its maximum amount, the device trigger isdelivered (310). Otherwise, the process of checking the UE state isrepeated (314). The counter can be set to be any number that would allowfor the efficient transmission of device trigger messages. Followingsuch a procedure waits for the destination UE of the device triggermessage to move from an idle state to a connected on its own, beforeforcing the UE to enter the connected state to receive the devicetrigger message.

Based on the solutions provided above, the UE State Information Requestflag can either be contained in an SIR (Subscriber Information Request)or in a new USIR (User State Information Request) message.Correspondingly, SIA (Subscriber Information Answer) or the new USIA(User State Information Answer) will contain the present UE stateinformation answer.

SIR and SIA are existing messages that are defined in TS 29.336 ofrelease 11 of the 3GPP standard. These messages will be enhanced inorder to reflect the UE state Information as follows. SIR will have newAttribute Value Pair (AVP) for the UE State Information Request flag;SIA will have new AVP for UE State Information Answer. USIR and USIA arenew messages that will be defined in future documents.

The User-State information can be one of the following states of the UE:

-   -   DETACHED    -   ATTACHED_NOT_REACHABLE_FOR_PAGING    -   ATTACHED_REACHABLE_FOR_PAGING    -   CONNECTED_NOT_REACHABLE_FOR_PAGING    -   CONNECTED_REACHABLE_FOR_PAGING    -   NETWORK_DETERMINED_NOT_REACHABLE

New state information can also be added as needed. For example, EMM_IDLEand EMM_CONNECTED. The HSS may not know the UE MM state information. Insuch a case, the HSS notification procedure can be enhanced to storeother UE state information, such as UE MM, SM state, and the like.

With reference to FIG. 4, a flowchart presenting the operation of anembodiment in which the MTC-IWF obtains the UE state from a MobilityManagement Entity (MME).

A Services Capability Server (SCS) determines the need to trigger thedevice (402). If the SCS has no contact details for an MTC-IWF, it mayfirst determine the IP address(es)/port(s) of an MTC-IWF by performing aDNS query using the External Identifier or using a locally configuredMTC-IWF identifier (404).

Thereafter, the SCS sends a Device Trigger Request message to theMTC-IWF (406). The message may contain information such as an ExternalIdentifier or MSISDN, SCS Identifier, trigger reference number, validityperiod, priority, trigger payload, and the like. The SCS includes aTrigger Payload that may contain the information destined for the MTCapplication, along with the information to route it to the MTCapplication.

The MTC-IWF checks that the SCS is authorized to send trigger requestsand that the SCS has not exceeded its quota or rate of triggersubmission over Tsp (408). If this check fails the MTC-IWF sends aDevice Trigger Confirm message with a cause value indicating the reasonfor the failure condition and the flow stops at this step.

The MTC--IWF sends a Subscriber Information Request (External Identifieror MSISDN and SCS Identifier) message to the HSS/HLR. to determine ifthe SCS is authorized to trigger the UE, to resolve the ExternalIdentifier or MSISDN to IMSI and retrieve the related HSS stored“Routing information” including the identities of the UE's serving CNnode(s) (410).

The HSS/HLR sends the Subscriber Information Response (IMSI and/orMSISDN and related “Routing information” including the serving node(s)identities, cause) message (412). The HSS/HLR policy (possibly dependenton the VPLMN ID) may influence which serving node identities arereturned. If the cause value indicates the SCS is not allowed to send atrigger message to this UE, or there is no valid subscriptioninformation, the MTC-IWF sends a Device Trigger Confirm message with acause value indicating the reason for the failure condition and the flowstops at this step.

The user state information Request message is sent from the MTC-IWF tothe MME, requesting the state of the UE (414). The information containedin this message is as explained above with respect to FIG. 2.

The User state information Answer message is sent as a reply to therequest from the MME, notifying it of the state of the UE (416). Theinformation contained in this message is again as explained above withrespect to FIG. 2.

The MTC-IWF now decides whether to buffer the trigger message or todeliver it, using the method explained above with respect to FIG. 3(418). After the MTC-IWF decides to send the trigger, it selects triggerdelivery procedure based on the information received from HSS and localpolicy. The T5 delivery procedure is selected and MTC-IWF attempts a T5trigger delivery procedure.

With reference to FIG. 5, a flowchart presenting the operation of anembodiment in which the MTC-IWF obtains the UE state from a PresenceServer.

A Services Capability Server (SCS) determines the need to trigger thedevice (502). If the SCS has no contact details for an MTC-IWF, it mayfirst determine the IP address(es)/port(s) of an MTC-IWF by performing aDNS query using the External Identifier or using a locally configuredMTC-IWF identifier (504).

Thereafter, the SCS sends a Device Trigger Request message to theMTC-IWF (506). The message may contain information such as an ExternalIdentifier or MSISDN, SCS Identifier, trigger reference number, validityperiod, priority, trigger payload, and the like. The SCS includes aTrigger Payload that may contain the information destined her the MTCapplication, along with the information to route it to the MTCapplication.

The MTC-IWF checks that the SCS is authorized to send trigger requestsand that the SCS has not exceeded its quota or rate of triggersubmission over Tsp (508). If this check fails the MTC-IWF sends aDevice Trigger Confirm message with a cause value indicating the reasonfor the failure condition and the flow stops at this step.

The MTC-IWF sends a Subscriber Information Request (External Identifieror MSISDN and SCS Identifier) message to the HSS/HLR to determine if theSCS is authorized to trigger the UE, to resolve the External identifieror MSISDN to IMSI and retrieve the related HSS stored “Routinginformation” including the identities of the UE's serving CN node(s)(510).

The HSS/HLR sends the Subscriber Information Response (IMSI and/orMSISDN and related “Routing information” including the serving node(s)identities, cause) message (512). The HSS/HLR policy (possibly dependenton the VPLMN ID) may influence which serving node identities arereturned. If the cause value indicates the SCS is not allowed to send atrigger message to this UE, or there is no valid subscriptioninformation, the MTC-IWF sends a Device Trigger Confirm message with acause value indicating the reason for the failure condition and the flowstops at this step.

The User State Information Request message is sent from the MTC-IWF tothe Presence Server, requesting the state of the UE (514). Theinformation contained in this message is as explained above. MTC-IWF canbe preconfigured with the address of the presence server. This step canhappen in parallel with 510.

The User state information Answer message is sent as a reply to therequest from the Presence Server, notifying it of the state of the UE(516). The information contained in this message is as explained above.

The MTC-IWF now decides whether to buffer the trigger message or todeliver it (518). This may be done following the method described abovewith respect to FIG. 3. After the MTC-IWF decides to send the trigger,the MTC-IWF attempts T5 trigger delivery procedure (520).

In some embodiments MTC-IWF may be arranged to communicate directly withthe UE and store the UE state information. In this case, UE sends thestate information directly to MTC-IWF and the MTC-IWF discoverymechanism by UE can be same as Presence Server discovery mechanism byUE. In some embodiments MTC-IWF and Presence Server can be co-located orimplemented in same box. In such an embodiment, not all functionalityneeds to be implemented in the same box. In other words, it may bepossible to implement part of functionality of Presence Server inMTC-IWF.

With reference to FIG. 6, a flowchart presenting the operation of anembodiment in which the MTC-IWF buffers the trigger in the MME. Itshould be noted that the MME is merely exemplary. The buffering nodecould also be SGSN or MSC.

A Services Capability Server (SCS) determines the need to trigger thedevice (602). If the SCS has no contact details for an MTC-IWF, it mayfirst determine the IP address(es)/port(s) of an MTC-IWF by performing aDNS query using the External Identifier or using a locally configuredMTC-IWF identifier (604).

Thereafter, the SCS sends a Device Trigger Request message to theMTC-IWF (606). The message may contain information such as an ExternalIdentifier or MSISDN, SCS Identifier, trigger reference number, validityperiod, priority, trigger payload, and the like. The SCS includes aTrigger Payload that may contain the information destined for the MTCapplication, along with the information to route it to the MTCapplication.

The MTC-IWF checks that the SCS is authorized to send trigger requestsand that the SCS has not exceeded its quota or rate of triggersubmission over Tsp (608). If this check fails the MTC-IWF sends aDevice Trigger Confirm message with a cause value indicating the reasonfor the failure condition and the flow stops at this step.

The MTC-IWF sends a Subscriber Information Request (External Identifieror MSISDN and SCS Identifier) message to the HSS/HLR to determine if theSCS is authorized to trigger the UE, to resolve the External Identifieror MSISDN to IMSI and retrieve the related HSS stored “Routinginformation” including the identities of the UE's serving CN node(s)(610).

The HSS/HLR sends the Subscriber Information Response (IMSI and/orMSISDN and related “Routing information” including the serving node(s)identities, cause) message (612). The HSS/HLR policy (possibly dependenton the VPLMN ID) may influence which serving node identities arereturned. If the cause value indicates the SCS is not allowed to send atrigger message to this UE, or there is no valid subscriptioninformation, the MTC-IWF sends a Device Trigger Confirm message with acause value indicating the reason for the failure condition and the flowstops at this step.

The MTC-IWF uses the UE capabilities, serving Core Network (CN) node(s)capabilities retrieved from the HSS to select a suitable serving CN nodecapable of T5 triggering (614). The MTC-IWF sends a Submit Request tothe serving CN node. The Submit Request may contain IMSI, messagepriority, MTC-IWF ID, reference number, single delivery attempt flag(optional), validity time (optional), Request type (triggerapplication), application PDU. If there is more than one serving CNnode, the MTC-IWF should send the message to the serving CN node wherethe UE is currently camping with highest probability. This may be, forexample, based on information received from HSS or cached informationfrom earlier trigger attempts.

The serving CN node indicates the Request type (trigger application),application PDU, MTC-IWF ID, Reference number within the NAS message anddelivers it to the UE (616). The serving CN node generates the necessaryCDR information (618), The UE provides the trigger content and triggertype to the corresponding application (620).

If the UE is in idle mode, the serving CN node may page the UE prior tosending a NAS message for delivering the trigger (622). If the UE is notin idle mode, it delivers the trigger (624).

If the UE is in idle mode, the MME decides whether to buffer the triggermessage or to deliver it. This may be accomplished according to a methoddetailed later in FIG. 7 or in a variety of other different ways.

The serving CN node sends a Delivery Report message to the MTC-IWF(626). The Delivery Report may contain several pieces of information,including IMSI, cause, reference number, delivered by CN node, Responsetype (trigger application), and if received, application PDU,information about buffering in MME). Cause indicates whether theTrigger-Message was successfully delivered to the UE or if it wasbuffered, or if failed, the reason for the failure.

The MTC-IWF then sends a report to the SCS informing it of the actionstaken (628).

With reference to FIG. 7, a flow chart illustrating the behavior of theMME depending on the status of the UE. After receiving the trigger(702), the MME checks the state of the UE (704). The priority of thedevice trigger is then checked (706). If the device trigger is high(708), then the device trigger is delivered (710). If the priority islow (712), then the UE state is checked (714). If the UE is connected(716), then the device trigger is delivered (710). If the UE is idle(718), then the device trigger is buffered in the MME (720). Then acounter is incremented (722). If the counter has reached its maximumamount, the device trigger is delivered (710). Otherwise, the process ofchecking the UE state is repeated (714). The counter can be set to beany number that would allow for the efficient transmission of devicetrigger messages. Following such a procedure waits for the destinationUE of the device trigger message to move from an idle state to aconnected on its own, before forcing the UE to enter the connected stateto receive the device trigger message.

The following examples pertain to further embodiments.

A Machine Type Communication Interworking Function (MTC-IWF) in an LTEnetwork may comprise: a processor arranged to: receive a device triggerrequest via the LTE network; validate the device trigger request;request status information of a user equipment (UE) to which the devicetrigger is to be sent; receive the status information of the UE; andsend the device trigger based on the status information; wherein thestatus information comprises information on the connection status of theUE. The status information may indicate if the UE is in an idle state orin a connected state. The MTC-IWF may be further arranged to: determinethe priority of the device trigger request and send the device triggermessage when the priority of the device trigger request is high. TheMTC-IWF may be further arranged to: determine the priority of the devicetrigger request; and when the priority of the device trigger request islow: send the device trigger request when the UE is in a connectedstate; and buffer the device trigger request when the UE is in an idlestate.

In another embodiment, a method for sending a device trigger message toa destination user equipment (UE) in an LTE network may comprise:receiving a request to send a device trigger message; determining thepriority of the device trigger message; transmitting the device triggermessage if the priority of the device trigger message is high; if thepriority checking of the device trigger message is low, checking if thedestination UE for the device trigger message is in a connected state;sending the device trigger message when the destination UE is in aconnected state; otherwise buffering the device trigger message untilthe destination UE is in a connected state.

In one embodiment, the method is performed by a Machine TypeCommunications Interworking Function (MTC-IWF). In one embodiment themethod is performed by a mobile management entity (MME).

In another embodiment, a method for sending a device trigger message inan LTE network may comprise: receiving a device trigger request;validating the device trigger request; requesting status information ofthe user equipment (UE) to which the device trigger is to be sent;receiving the status information of the UE; and sending the devicetrigger based on the status information; wherein the status informationcomprises information on the connection status of the UE.

In one embodiment, the status information indicates if the UE is in anidle state or in a connected state.

In one embodiment, sending the device trigger based on the statusinformation comprises: determining the priority of the device triggerrequest; and sending the device trigger message when the priority of thedevice trigger request is high.

In one embodiment, sending the device trigger based on the statusinformation comprises: determining the priority of the device triggerrequest; and when the priority of the device trigger request is low:sending the device trigger request when the UE is in a connected state;and buffering the device trigger request when the UE is in an idlestate. In one embodiment, buffering the device trigger request isperformed by a Mobile Management Entity (MME).

In one embodiment, the method may further comprise: creating a reportdetailing the sending of the device trigger; and creating a chargingdata record (CDR) based on the sending of the device trigger.

In one embodiment, the method is performed by a Machine TypeCommunication Interworking Function (MTC-IWF).

In one embodiment, requesting status information of the user equipment(UE) to which the device trigger is to be sent may comprise sending asubscriber information request (SIR) message to a Home Subscriber Server(HSS); and receiving the status information of the UE may comprisereceiving a Subscriber Information Answer (SIA) message from the HSS.

In one embodiment, the SIR message comprises a state information requestof the UE; and the SIA message may comprise state information of the UE.

In one embodiment, the state information comprises information regardingwhether the UE is in an idle state or in a connected state.

In one embodiment, the state information is selected from the following:detached, Attached_Not_Reachable_For_Paging,Attached_Reachable_For_Paging, Connected_Not_Reachable_For_Paging,Connected_Reachable_For_Paging, and Network_Determined_Not_Reachable.

In one embodiment, requesting status information of the user equipment(UE) to which the device trigger is to be sent may comprise sending asubscriber information request (SIR) message to a Mobile ManagementEntity (MME); and receiving the status information of the UE comprisesreceiving a Subscriber Information Answer (SIA) message from the MME.

In one embodiment, requesting status information of the user equipment(UE) to which the device trigger is to be sent comprises sending asubscriber information request (SIR) message to a Presence Server; andreceiving the status information of the UE comprises receiving aSubscriber Information Answer (SIA) message from the Presence Server.

In one embodiment, requesting status information of the user equipment(UE) to which the device trigger is to be sent may comprise sending asubscriber information request (SIR) message to a Home Subscriber Server(HSS); and receiving the status information of the UE comprisesreceiving a Subscriber Information Answer (SIA) message from the HSS.

In another embodiment, a method may comprise: receiving a device triggerrequest; validating the device trigger request; requesting statusinformation of the user equipment (UE) to which the device trigger is tobe sent; receiving the status information of the UE; and submitting arequest to a mobile management entity to process the device triggerrequest.

In one embodiment, the method is performed by a Machine TypeCommunication Interworking Function (MTC-IWF).

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents may occur to those skilled in the art. It is, therefore, tobe understood that the appended claims are intended to cover all suchmodifications and changes as fall within the scope of the invention.

We claim:
 1. A Machine Type Communication Interworking Function(MTC-IWF) in a Long Term Evolution (LTE) network comprising: a processorarranged to: receive a request to send a device trigger message via theLTE network; validate the request to send a device trigger message;request status information of a user equipment (UE) to which the devicetrigger message is to be sent; receive the status information of the UE;and send the device trigger message based on the status information;wherein the status information comprises information on a connectionstatus of the UE.
 2. The MTC-IWF of claim 1 wherein the statusinformation indicates if the UE is in an idle state or in a connectedstate.
 3. The MTC-IWF of claim 1 wherein the MTC-IWF is further arrangedto: determine a priority of the request to send a device triggermessage; and send the device trigger message when the priority of therequest to send a device trigger message is high.
 4. The MTC-IWF ofclaim 1 wherein the MTC-IWF is further arranged to: determine a priorityof the device trigger request; and when the priority of the devicetrigger request is low: send the device trigger message when the UE isin a connected state; and buffer the device trigger message when the UEis in an idle state.
 5. A method for sending a device trigger message toa destination user equipment (UE) in an LTE network comprising:receiving a request to send a device trigger message; determining apriority of the device trigger message; transmitting the device triggermessage if the priority of the device trigger message is high; if thepriority of the device trigger message is low, checking if thedestination UE for the device trigger message is in a connected state;sending the device trigger message when the destination UE is in aconnected state; otherwise buffering the device trigger message untilthe destination UE is in a connected state.
 6. The method of claim 5wherein the method is performed by a Machine Type CommunicationsInterworking Function (MTC-IWF).
 7. The method of claim 5 wherein themethod is performed by a mobile management entity (MME).
 8. A method forsending a device trigger message in a Long Term Evolution (LTE) networkcomprising: receiving a request to send a device trigger message;validating the request to send the device trigger message; requestingstatus information of the user equipment (UE) to which the devicetrigger message is to be sent; receiving the status information of theUE to which the device trigger message is to be sent; and sending thedevice trigger message based on the status information; wherein thestatus information comprises information on the connection status of theUE.
 9. The method of claim 8 wherein the status information indicates ifthe UE is in an idle state or in a connected state.
 10. The method ofclaim 8 wherein sending the device trigger based on the statusinformation comprises: determining the priority of the request to send adevice trigger message; and sending the device trigger message when thepriority of the request to send a device trigger message is high. 11.The method of claim 8 wherein sending the device trigger message basedon the status information comprises: determining the priority of therequest to send a device trigger message; and when the priority of therequest to send a device trigger message is low: sending the devicetrigger message when the UE is in a connected state; and buffering thedevice trigger message when the UE is in an idle state,
 12. The methodof claim 11 wherein buffering the device trigger message is performed bya Mobile Management Entity (MME).
 13. The method of claim 8 furthercomprising: creating a report detailing the sending of the devicetrigger message; and creating a charging data record (CDR) based on thesending of the device trigger.
 14. The method of claim 8 wherein themethod is performed by a Machine Type Communication InterworkingFunction (MTC-IWF).
 15. The method of claim 14 wherein: requestingstatus information of the user equipment (UE) to which the devicetrigger message is to be sent comprises sending a subscriber informationrequest (SIR) message to a Home Subscriber Server (HSS); and receivingthe status information of the UE to which the device trigger message isto be sent comprises receiving a Subscriber Information Answer (SIA)message from the HSS.
 16. The method of claim 15 wherein the SIR messagecomprises a state information request of the UE; and further wherein theSIA message comprises state information of the UE.
 17. The method ofclaim 16 wherein the state information comprises information regardingwhether the UE is in an idle state or in a connected state.
 18. Themethod of claim 17 wherein the state information is selected from thefollowing: detached, Attached_Not_Reachable_For_Paging,Attached_Reachable_For_Paging, Connected_Not_Reachable_For_Paging,Connected_Reachable_For_Paging, and Network_Determined_Not_Reachable.19. The method of claim 15 wherein the SIR message is a User StateInformation Request (USIR) message; and the SIA message is a User StateInformation Answer (USIA) message.
 20. The method of claim 14 wherein:requesting status information of the user equipment (UE) to which thedevice trigger message is to be sent comprises sending a subscriberinformation request (SIR) message to a Mobile Management Entity (MME);and receiving the status information of the UE comprises receiving aSubscriber Information Answer (SIA) message from the MME.
 21. The methodof claim 14 wherein: requesting status information of the user equipment(UE) to which the device trigger is to be sent comprises sending asubscriber information request (SIR) message to a Presence Server; andreceiving the status information of the UE comprises receiving aSubscriber Information Answer (SIA) message from the Presence Server.22. The method of claim 14 wherein: requesting status information of theuser equipment (UE) to which the device trigger message is to be sentcomprises sending a subscriber information request (SIR) message to aHome Subscriber Server (HSS); and receiving the status information ofthe UE comprises receiving a Subscriber Information Answer (SIA) messagefrom the HSS.
 23. A method comprising: receiving a request to send adevice trigger message; validating the request to send a device triggermessage; requesting status information of the user equipment (UE) towhich the device trigger is to be sent; receiving the status informationof the UE; and submitting a request to a mobile management entity toprocess the request to send a device trigger message
 24. The method ofclaim 23 wherein: the method is performed by a Machine TypeCommunication Interworking Function (MTC-IWF).